Means for mechanically focusing photographic lenses.



Y L. LR. HOLST. MEANS FOR MECHANIOALLY rocusme PHOTOGRAPHIO LENSES.

APPLICATION FILED OUT. 30, 1911. 1 Patented June 11, 1912.

4 SHEETS-SHEET 2.

awn/2 A TTORNE Y L. J. R. HOLST.

MEANS FOR MEOHANIOALLY FOGUSING PHOTOGRAPHIO LENSES.

APPLICATION FILE-D 0GT.30,1911.

I WlTNESZSti-IS rA-VWW-n: YMNWH,

, L. J. R. HOLST.

MEANS FOR MEGHANIOALLY FOGUSING PHOTOGRAPHIG LENSES.

APPLICATION FILED on. 3.0, 1911.

1,029,297, Patented June.11,191 2.

4 SHEETSSHEET 4.

N VE N TOR ZM f #444 M4 4. %l A TTORN E Y WITNESSES fully understood from the UNITED STATES Tau stains.

LODEWYK J. B... HOLST, 0F LANSJUDWN'E, PiEEEISYLIVANHa, AEESIGNOR T0 WILLIAMS,

BROWN AND. EAELE, INC., 05 PHILADEEEEIA',PENNSYLVANIA,

OF PENNSYLVANIA.

A GGRPORA'JION MEANS FOR MEUHATIICALLY' FGCUESING PHQI'UGBZsEHIC LENSES.

Specification of letters Patent.

Patcnteddune 11, 1912,

Application filed D'otbher 30, 3.931. sarisi H0. 657,633.

Toall whom it may concerts:

Be it known that I, LonEwYK J. R. Hon-s2, a citizen oi the United States, residingat- Lansdown'e, in the county of Delawere and State of Pennsylvania, have in. rented certain new and useful Improve ments in Means for Mechanically Focusing. Photographic Lenses, of which the following is. a specification.

My present invention is based in principle upon the art of mechanically focusing photographic lenses forming the subjectmatter of an application "for United States Letters Patent. Serial No. 640,902., filed by me under" date of July 27th 1911, in which the focusing ofphotographic lenses is medicated u n mechanicall establishin 1 other the same mathematical relation as the principal focus bears to the cori'jugatestoci, diminished by the focus-,and which relations are maintained in all positions of the apex when shifted parallel to the hypotenuse; and iny present invention in particular, em; bodies mechanisms for carrying into eitect the-said aforementioned application.

The. nature scope and characteristic features of my present invention will be more following I description taken in connection with the accompanying drawings formingpart her of, li'l'\Vl1i0lI- Figure 1, is a longitudinal side elevationazl view of the focusing mechanism, showing in. part a stand-or bracket for its support. Fig. 2,3is a plan view of Fig; 1, the lens illuminating device and plate carriers. being removed. Fig. 3, .isan end elevational view in which the lamp house, is removed; and Fig. 4; is an endelevationaivieu with the lamphouser'in position, and the rear does therecdZ-removed.

Beierringto the drawingsswith reference particularly to Fig. 1, 5 is the stand or bracket upon which the mechanism is held in position. (in it is placed the support or frame part 6, which is provided with two sets of guide ways, formed preferably by the outer edges 6 0; the bed proper, and by parallel strips 6* projecting inwardly from the sides of the frame as clearly shown in Fig. 3. The inwardly projecting guide ways support a slide 7', which carries on its forward end the lei-s support 7*, and directly behind that a bracket 9, supporting a transversely projecting pivot-pin 9 as clearly shown in Fig; 2. This slide 7 will be referred to as the lens-slide. 0n the guide ways 6- formed by the top of the frame 6; a carriage 8 is mounted; two grooved 8 and 8, and one flat rimmed wheel 8, placed on the opposite guide ways Fig. 2) permitting this carriage to be easily moved back and forth over the frame 6 The: carriage 8, is provided on either side with a downwardly projecting arm 8*, from which pivoted arms 8 projectforwardly, to support flat rimmedrollers 8 and 8 which are pressed against the bottom surfaces of the guide ways 6 by means of springs 8. 011 its top surface, the carriage 8, supports the plate or object carrier 8, behind which further be reieiaed to as the plate-carriage The forward end of the lamphouse 19, is slipped over the condenser casing to assure a light-tightconnection between these parts. The la'mphouse projects beyond the rear end of the carriage and is supported on a roller. 5*, pivoted on a suitable bracket 5*, attached to the stand 5. This arrangement perm-its of moving the lamp'house back and tort-h with the condenser. whereas the illuminating device 20', which may be of any convenient kind or type, is independently adjustable with regard to the condenser or objectpla-te by the device now to be described.

I am aware that ithas been proposed to attach the illuminating device to the plate carrier to cause it to move in unison with the object:

although this arrangement is suitable for f) the usual con-f denser 18, is placed. This carriage will plate and the condenser and mousing mechanisms having a comparatively small range of adj ustinent; I find that in constructiczcs as these now being described, and which are capable of a'wide range of adjustments,giving both enlarge ments and reductions, the lens assumes such widely different positionswith relation to the condensers, that it is desirable to provide means whereby the illuminating evice is caused to be fixed distance behind the object.

suit-able slots.

The bottom surface of the lamphouse 19,

supports in convenient positions the-chain wheels 19 and 19, (Figs. 1 and 4), which partly project inside the lamphouse through The spindle of the chain wheel 19 is prolonged to support also the larger chain wheel 7 A chain 7 passes over this wheel and is attached to a suitable pin 7, projecting outwardly from the lens I support 7*, and a suitable weight 7 is suspended from the free end of this ,chain.

The small chain wheels 19 and 19", are

connected by an endless chain 19 whichpasses over the' base 20, slidably adjustable over the bottom of the lamphouse 19, be.-

' inciding .of the Wheels 19 relation of the focal tween suitably shaped guiding strips less chain 19?. It is thus evident that when the distance between the lens and the objectilluminating device is the condenser-18, and

is increased the caused to approach that when lens and cause 'the illuminating device to recede from the condenser. The relative diameters and 7?,

condensers used, and may be 1 determined most easily by actual experiment, as the uncorrected optical properties of condensers make computation too uncertain and complicate.

In Fig. 1,the dot and dash lines indicate the'path of the light from the illuminating the condenser 18, to the device 20, through lens '7, the apex of this bundle of light cowith the focal point of the lens 7', when the latter is moved in the position of its nearest approach to the condenser 18,

vice 20, is moved toward oscillatory slide block 11 is provided.

the lens is moved while the dotted lines indicate that when condenser 18, to coincide with the apex formed by these lines, the illuminating dethe condenser into its proper corresponding position.

Near the forward end of the frame 6,

is later referred to as the fulcrum. A similar slide block 12 is supported by a bracket 13, attached to the carriage driving point for this carriage. blocks are enga ed by a pair of guide rods 11 and 12, whic held at right angles angle plate 10, which to each other in the adjusted in harmony with the lens-movement, and not kept at a 19. A clamp-plate and screw. 20", when tight ened down,.attach the base 20*, to the end-,

object move toward. each other the action of the weight '2' will depend upon the lengths of the lens and of the plate-carriage farther apart from thean This 7 8, and forms the These slide are accurately and rigidly is pivoted on the, p v t.

9, previously mentioned and forming the driving point ofthe slide. The center of the pivot-hole in the angle plate 10, coincides exactly" with the intersection of the axes of the rods 11 and 12. A link rod 17, connects the pivot-pin 9 in 1 intermediate the pivot-pin 16 and the slide block 14 of the lever 14:. The

with the pivotslide block 14 is pivoted on the bracket 13, p

and the pivot-pin 16, is carried by the upper end of the operating lever 15, which in its turn is pivoted on the spindle 15 carried by the support 5. The cooperation of this system of levers causes the lens-slide 7, and the plate-carriage 8, to move with such relative velocity that the lens and object. respectively carried on these latter parts, at all times assume the proper relative positions to project a sharp image, either of increased, reduced or equal size as the original, on a stationary image receiving surface,

suitably placed with relation to the other i elements, in accordance with the theoretical conditions fully developed in my pending application for a United States Patent, Serial No. 640,902,filed by me July 27th, 1911.

The mode of operation of the focusing means as illustrated and described, is as follows :First, the height of the pivot-pin 9?, on which the two slide-rods'11 and 12, are suspended is adjusted so thatthe distance of its center, point ofthe lens-slide 7, above the line uniting the centersof the oscillating guides 11 and 12 of the slide-rods 11 and 12, is

exactly equal to thefprincipal focal length of the lens used; then the operating lever 15, is moved until the distance pivot-pin 9, and the centers of each of the oscillating guide block-bearings 11 and 12*, that is, the fulcrum and the driving point are exactly equal. The centers of these three elements will then form an isosceles right-angle triangle; the base of which equals twice'the focal ;length, asformerly established. With themechanism in this adjustment, which is then stands adjusted to produce an imageequal in size to 'the'object and is ready for operation by means of the crank-handle 15. In moving the same toward the image, that is, to t e left in Fig. 1,-it will caus'ethe lens which forms the driving 5 between the at a distanceequal to twice the.

measured to approach the image through theefl'ect of the double-armed lever-rod l4, and the connecting-rod 17, acting on the lens drivingpoint '9 of the plate-slide 7. At the same time, the forward slide rod- 11, will glide .oscillatingly through its fulcrum 11 and assume a more upright position causing the other slide rod 12, to assume acorrespondingly increased slanting position toward the horizontal and driving thereby the platecarriage 8, farther away from the lens 7, in which movement it is assisted by the action of the lower end of the double-armed lever-rod l4. Theadjustments previously carried out cause the movement of the plate-carriage 8,. with the object-support attached thereto, to remain continuously in proper relation to the movement of the lens-slide 7, supporting the lens 7, so that the image will remain sharp, while constantly changing in size within the limits of. the capacity of the-mechanism.

a Fig. 1, shows the mechanism in that limit of its adjustment vwhich coincides with the maximum magnification for whichthe, instrument .1s designed, and on moving the crank-handle'15 toward the left, the lens and the objectrplate will both move toward.

the image, the lens moving faster than the plate. This condition will prevail, until the position for reproduction in equal size has been reached,,in which position the rods 11 and 12, make each an angle of 45, with the imaginary line uniting the centers of the oscillatory guide blocks 11 and 12. On continuing the movement of the crank handle 15 in the same direction. beyond this point, the lens will continue in its course toward the image, but the objectplate will now begin to retrace its former course, increasing thereby not only the dis-' tance between the plate and the lens, but also between theplate and the image, a ll of which is in full accordance with the mathe matical requirements of the equivalent foci. The continued movement of the handle 15", causes thusthe lens and the plate to first move in the same direction and later in opposite direction or vice versa, whereas the handle 15*, moves in the same direction from end to end of its course. It should furthermore be observed, that inasmuch as the focusing mechanism is designed to maintain the correct conjugate distances after their original establishment. as described, it is lmmaterial which actual place the lensoccupieswith relation to the lensslide, so long as it derives its movement froni the movement of the slide. It may any point of the slide, on the condition that when placed in the unit position, it will be at exactly double the focaldistanee from the object surface, theearrier for which latter can thus equally 15 i tached to whatever the position of the 12*, form the the rectangular sides.

- base-line 11*,

any p int or the riage, so long as it derives its movement from the latters movement.

The foregoing description of the construction and of the mode of operation of this mechanism, will be still better understood when observing that in Fig. 1, the elements 9, ll 'and 12*,or respectively, the driving point of the lens-slide, the fulcrum and the driving point of the plate-carriage always form together a rectangular triangle pivot 9 may be, the imaginary line passing through the centers of the guides 11 and 12 formin the base-line, which line is parallel to the bed 6. The centers of the guidesll and ends of the hypotenuse, the center of the pivot 9 being the apex and the center lines of the rods 11 and 12, being The apex being slidable in a line parallel to the hypotenuse,the perpendicular erected on the imaginary 12*, through the apex 9, will at all times divide the distance between the centers of the guides 11 and 12, in lengths to which theheight of the apex, above the said base-line, is middle proportionate, in accordance with the well knowngeometrical theorem, that in a rectangular triangle the perpendicular on the hypotenuse passing'through the intersection of the rectangular sides, divides the hypotenuse in sections which are respectively directly and inversely proportionate to thelength of such perpendicular. The distance between ,the centers of the guides .11 and 12* will vary, in accordance with the position ,of the driving point 9 of the lens-slide, and may thus always be considered as being composed of two parts, divided bythe projection of the center of the pivot 9 on the imaginary base-line 11*, 12, one part being the hori-' zontal proiection of the rod 11 on'the line 11, 12 the other part being the horizontal projection of the rod 12 on the same line, so that the sum of these two horizontal proiections constitutes at'all times the entire distance between the centers iof the guides 11 and 12.

Although the mechanism as described and illustrated is of preferred'construction, it. is nevertheless obvious that it may be modified to suit different purposes without thereby departing from the nature as well as scope of my said inventiom'as defined by the claims.

Having thus described the nature and objects of my invention, what I claim as new and desire to secure by LettersPatent is 1. In a focusing apparatus, a frame, a lens-slide mounted on said frame, a plate-- carriage mounted on said frame, means to impart movement to said slide, means also to impart relative movement to said platecarriage, said means being pivotally connected to each-of said tWo'last-named memminus the focus.

driving point 2. In a focusing apparatus, a frame'carrying a fulcrum for a sliding-rod, a lensslide and a plate-carriage movable on said frame, means to impart movement to said lens-slide, means also to impart relative ,movement to said plate-carriage, said means being pivotally connected to each-of said two last-named members at a fixed driving point or axis on each and being adapted to automatically maintain the distance between said fulcrum and the projection of the driving point on said lens-slide on a-line passing through the center of said fulcrum parallel to the frame always equal to the length of one of the con ugate-foci, minus thefocus. V

g3. In a focusing apparatus, a frame can rying a fulcrum for a slide-rod, a lens-slide and a plate-carriage adapted to move along said frame, means to impart movement to said lens-slide, means'also to impart relative movement to said plate-carriage, said means being pivotally connected .to each of said two last-named members at .a fixed or axis on each and being adapted to automatically maintain thedistance between said fulcrum and the projection of the driving point on the lens-slide on a line passing through the center of said fulcrum parallel to the frame always e ual to the length of one of the conjugateoci, minus the focus, and to automatically maintain the corresponding distance, between similar projections of the driving points on said lens-slide and plate-carriage always equal to the length of the other conjugateother,

focus, minus the focus.

4. In a focusing apparatus, a frame, a lens-slide carrying a pivot and a platecarriage cooperating with saidlframe, a set of rods arranged at right angles to each rotatably suspended at the point of intersection of said rods on the pivot of said lens-slide, an oscillatory guide block pivoted on said frame, and an oscillatory guide block pivoted on said plate-carriage, each of said oscillatory guide blocks engaging one of said rods, to thereby control the relative movement of said lens-slide and plate-carriage.

5. In a focusing apparatus, a .frame carrying a fulcrum, comprising an oscillatory guide block, a lens-slide carrying a laterally projecting pivot-pin, a plate-carriage having an oscillatory guide block, said lensslide and plate-carriage adapted to travel on the along said frame, rods rotatably suspended pivot-pin of said lens-slide, said rods arranged at right angles to each other, and

respectively'engaging said oscillatory guide blocks, controlling thereby the relative movements of said lens-slide and plate-carriage, operating means, adapted when moved in one direction to shift the suspension point of said rods to cause the driving point of said lens-slide to continually approach said fulcrum and the driving point of said plate-carriage to first approach, and then to recede from said fulcrum and vice versa, upon reversing the direction of movement of said operating means, to maintain between the driving points of said lens-slide and plate-carriage, distances, the projections of which, on a line passing through said fulcrum, parallel to the frame, will always be conjugate to the corresponding distances between said fulcrum and the similar projections of the driving point of said lensslide.

6. In a focusing apparatus, a frame having guide-ways, a lens-slide supporting a pivot and adapted to travel along said guide ways, a lens-carrier operatively connected with said lens-slide, a plate-carriage adapted to travel along said'frame, an object-can rier operatively connected with said platecarriage, rods arranged at right angles with each other and operatively connected with the pivot of said lens-slide, plate-carriage and frame, and operating means adapted to shift the pivot of said rods by one continuous forward movement, or by one continuous backward movement, to cause said lens-slide and plate-carriage to move partly in the same direction, and then in opposite directions, or vice versa, through the entire range of their relative adjustments from maximum magnification to maximum reduction.

7. In a focusing apparatus, the combination of a frame, a lens-slide mounted on said frame, a plate-carriage also mounted on said frame, a condenser supported by said carriage, an illuminating device movably connected with said carriage, and operat-iveconnections between said lens-slide, plate-carriage and illuminating device, to cause the distance between the illuminating device and the condenser to decrease or to increase, in accordance with the increase or the decrease of the distance between said condenser and lens-slide.

In witness whereof, I have hereunto set my signature in the presence of the two subscribing witnesses hereto.

THOMAS M. SMITH, HELEN F. MILLER. 

